Shear stress with hydrogen, not oxygen, matters to the fatigue lifetime of silicon

This paper presents a new discovery over a long-lasting mystery of fatigue mechanism in silicon. We found that fatigue degradation possibly takes place due to defect accumulation in crystal with the aid of not only humidity but also hydrogen as well, and shear stress which is newly discussed in this study. Fatigue lifetime was eventually shorter with larger shear stress working on the crystal slip plane. Striation-like fracture surface patterns generated before unstable fracture were also discovered. Now we know that silicon may behave in a much more metallic manner with the aid of hydrogen even at room temperature than ever believed before, no wonder leading to fatigue fracture.